The present invention pertains to a joining device and joining method for joining a resin member and metal member using a fastener. More particularly, the invention pertains to a joining device and joining method for joining a resin member and metal member whereby a fastener is press-fit from the resin member side, and the fastener and the metal member are welded to join the resin member and the metal member.
Joining methods for joining a resin member and a metal member include screw fastening, rivet punching, adhesion and the like. Screw fastening is accomplished by pre-drilling a swaging hole in a resin member and a metal member, matching the positions of the holes in the resin member and the metal member, inserting a screw into the hole formed in the resin member from the resin member side and affixing the screw by screwing it into the hole formed in the metal member. However, fastening by screw requires formation in advance of screw holes in the resin member and metal member, which is laborious. It is also difficult to match the screw position to the screw holes in the resin member and metal member for screwing in. The presence of the screw hole makes it difficult to maintain waterproofness and airtightness.
In rivet punching, a rivet is punched in from the resin member side through to the metal member to join the resin member and the metal member. With rivet punching, there is no need to drill holes in the resin member and the metal member; wherefore, the resin member and metal member can be joined in a simple manner. The problem arises, however, that cracks can easily form in the resin member during riveting if the resin member is rigid. It is also easy for gaps to form between the rivet and the resin member and metal member, making it difficult to maintain waterproofness and airtightness.
With adhesion, an adhesive is applied to the resin member and/or the metal member, and the resin member and metal member are laminated and adhered via the adhesive. Adhesion requires pre-drilling of holes in the resin member and the metal member. In adhesion, however, the application of the adhesive is laborious, and processing such as heating or applying pressure and clamping are required to cure the adhesive, thus requiring time.
Japanese published unexamined Patent Application S.61-269986 discloses a method for laminating a non-conductive rigid member and a metal member and inserting a metal fastener from the rigid member side to connect to the metal member. In this method, the rigid member is laminated to the metal member; one electrode on a welding machine main unit is connected to a metal base material, and the other electrode is connected to a pressure member on a press brake. A cylindrical metal fastener is press-fit from the surface of a rigid member toward a metal base material by the pressuring member on a press. Electricity is applied to perform welding between the two when the tip portion of the cylindrical metal fastener reaches the metal member.
Prior art JP S.61-269986 describes continued press-fitting of a metal fastener by the pressuring member of a press for a certain time period following start of spark so that the metal is made sufficiently molten, thus enabling a strengthening of the joint between the rigid member and the metal base material.
In JP S.61-269986, however, electricity is applied and welding performed after the tip portion of the metal fastener reaches the metal base material, and no heating of the metal fastener is done when the metal fastener is press-fit into the rigid member. Hence, cracking can occur or fissures can enter the rigid member when a metal fastener is press-fit into the rigid member.
Patent Document 2 discloses a stud welding device in which pre-heating and heating burners are attached to the tip-side portion of a welding gun. In Patent Document 2, pre-heating and post-heating of a welding portion during stud welding can be accomplished by a pair of heating burners attached to the tip-side portion of a welding gun, and as there is no sudden heating or sudden cooling, cracking can be prevented and welding work efficiency improved.
The stud welding device of prior art Utility Model JP S.61-82775 heats a member from its surface by a heating burner to weld studs; it does not weld two laminated plate-shaped members.
The device of JP S.61-82775 uses a gas burner as a heating burner and therefore requires a gas cylinder. Further, when two plate-shaped members are welded by the device of JP S.61-82775 U, heating is performed from the top of the upper member; therefore, the lower member is not heated sufficiently, and it is difficult to weld the two plate-shaped members.
Prior art Utility Model JP H.2-93087 discloses a welding machine with which a favorable welding state is obtained by imparting a shock to a welding pin, driving the pin tip into a metal surface. In JP H.2-93087 U, a striking device for imparting a shock to a welding pin is provided; a shock force is imparted to the welding pin, the tip of the welding pin is driven into a metal surface, then electricity is supplied to perform resistance welding. The reference therefore states that good contact between the welding pin tip and the metal surface is achieved, and good welding is performed even if the metal plate surface is coated with insulation or rust.
However, JP H.2-93087 U does not provide for the heating of the welding pin prior to welding. Therefore, if the member covering the metal member is rigid, there is a risk of its cracking when a welding pin is driven into a member on the metal member.
Thus, in JP S.61-269986, resistance welding is performed after the metal fastener contacts the metal base material; the rigid member is not heated when the fastener is press-fit into the rigid member. In JP S.61-82775 U, a steel surface is heated by a heating burner at the time of stud welding; welding of two plate members is not performed. In JP H.2-93087 U, resistance welding is performed after applying a shock to a welding pin to drive it in; as in JP S.61-269986, no heating is performed when the welding pin is driven in.
Therefore, a method, joining structure and joining device with a low tendency to crack resin members and capable of simple joining have been sought.
A joining device and joining method capable of stable joining of a resin member and metal member with high strength have also been sought.